The present invention relates to a facsimile apparatus, copier, printer or similar image forming apparatus and, more particularly, to a catch type sheet tray mounted on an image forming apparatus for accommodating sheets sequentially driven out of the apparatus by holding the leading edges thereof.
Generally, sheets sequentially driven out of a facsimile apparatus, for example, are accommodated in either of a horizontal tray and a catch type tray. The horizontal tray simply stacks the sheets delivered thereto along a horizontal path. On the other hand, the catch type tray catches the leading edges of the sheets and causes the trailing edges of the sheets to hang down to the outside of the tray. The catch type tray is advantageous over the horizontal tray in the space saving aspect.
However, the catch type tray has some problems left unsolved, as follows. This type of tray is usually constructed integrally with the body of the image forming apparatus, and sheets have to be accommodated in the tray without exception. Hence, when sheets are longer than the tray, they have to be held by the tray in a bent position and, therefore, suffer from curls which render handling difficult. When more than the number of sheets which the tray can accommodate are discharged from the apparatus, the excess sheets bulge out from the tray and drop onto the floor. Further, while the apparatus body is discharging sheets, a roller included in the tray for catching sheets is continuously rotated. This brings about a problem that when more than the predetermined number of sheets are driven out of the apparatus, the roller is apt to scratch or otherwise damage the last sheet caught. Moreover, such a roller is likely to roll up sheets more than necessary since a driving force i s constantly transmitted thereto. In addition, with the catch type tray, it is impossible for a person to return the sheets to the tray after separating only the sheets addressed to him. The person, therefore, has to deal with even the sheets addressed to other persons.
Techniques relating to the catch type tray are taught in, for example, Japanese Utility Model Publication Nos. 668/1988 and 6118/1988, Japanese Patent Publication Nos. 2862/1988, 8023/1988, 56149/1988 and 55115/1989, Japanese Patent Laid-Open Publication (Kokai) Nos. 101263/1988, 218463/1988 and 267259/1991. These prior art techniques allow sheets driven out of the apparatus to be accommodated in the correct order, while saving the overall space for installation and operation. However, even such elaborated approaches cannot eliminate the problems discussed above.